Indication of thrombolysis for middle cerebral artery occlusion using MR diffusion - weighted image

We have evaluated the usefulness of diffusionweighted MRI (DWI) for determining an indication of emergent thrombolytic revascularization therapy in patients with acute occlusive cerebrovascular disease. Out of twenty-nine patients with acute occlusion of the middle cerebral artery within six hours after the onset, nine patients performed thrombolytic therapy. In results, seven patients of them obtained revascularization and good outcome. DWI findings on admission were correlated to the cerebral blood flow measured by SPECT and classified into four types; Type 1: no high intensity, Type 2: high intensity only in the perforator's territory, Type 3: limited high intensity in the cortical branches' territory, Type 4: extended high intensity. As presented cases, the high intensity area seen on DWI became obvious infarction regardless of implementation of revascularization therapy. However, thrombolytic therapy could rescue the area of low CBF on SPECT and could improve clinical symptoms. We considered that the area of low CBF without high intensity on DWI was "ischemic penumbra" and classification of DWI findings could be a valuable indicator in determining an indication of thrombolytic therapy.